Accounts Receivable, net - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
Write-offs of accounts receivable	$ 500	$ 400
Provision for doubtful accounts	303	401
Restaurant/Retail
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowances for doubtful accounts	$ 900	$ 900